Can you use a character for animation and 3d printing?
There should be no problem using a rigged character for 3D printing, assuming the character's mesh is suitable for printing (no holes, no non-manifold geometry, consistent normals pointing in the right direction, correct scale, etc).

To make sure all is prepared, you can make a copy of each pose to a new duplicate model, apply the Armature Modifier and delete the armature object (to clean up the scene), run printability tests via the 3D Printing Toolbox addon or an external program (Netfabb, Meshmixer, etc) and export your STL.